Fluorescent lamps and fluorescent lamp based products, such as for example low energy lamps, sodium lamps, lamps with fuses comprising mercury and traditional mercury lamps are common today. This type of lamps often contains mercury, which is a chemical element which is both poisonous and hazardous to the environment. For example fluorescent lamps usually comprise mercury in the form of mercury vapour in order to achieve fluorescence from a so called luminescent material which is located on the inside of the tube. The luminescent material which in itself may comprise mercury is contained in the lamps and is hence needed for the lamps to emit light.
Mercury may also occur in electronic products, such as for example relays, electrical switches, thermostats and displays. For example the background lighting of LCD-screens usually comprises mercury. Measurement instruments, such as thermometers and barometers, are other examples of products that may contain mercury.
Since mercury is poisonous and hazardous to the environment it is from an environmental and health aspect desirable to recover material in used lamps of this type to an as high degree as possible and in such a manner that mercury is not spread to the surroundings.
In a known treatment process for recovering used fluorescent lamps, fluorescent lamps are crushed and treated with a solution of chemicals with the purpose of binding mercury for terminal storage. In this process metallic mercury is bound to sulphide for forming mercury sulphide. Mercury in this form is, however, very difficult to recover and will hence require complicated processes.
The mercury sulphide is therefore transported to terminal storage, while metal and glass is washed, screened and recovered in the glass, glass wool and metal industry.